Several classes of biologically active terpenes which contain a cyclooctane ring, typically within a bicyclo[6.3.0]undecane substructure, have been identified. These classes include antibiotics such as pleuromutilin and the ophiobolins, along with structurally simpler congeners such as dactyol. The synthesis of the central bicyclo[6.3.0]undecane carbocyclic skeleton via a novel, direct intramolecular[6Pi + 2Pi] photocycloaddition of 2-alkenyl tropones is described. A study of further transformations of these cycloadducts, including the total synthesis of dactylol, is proposed.